The present invention relates to curtain walls, and more particularly to a self-bearing flexible curtain wall system for cladding a structure.
In the construction of enclosed buildings, it is generally most efficient to construct the columns, floors, roof, and internal supporting walls initially, and, thereafter to enclose the structure by constructing the exterior walls. A curtain wall system is an exterior wall system (i.e., a cladding) installed outboard of the building perimeter frame to provide protections against the exterior weather conditions. In addition to a traditional utilitarian function, curtain wall systems are further called upon to satiate aesthetic functionality.
Curtain wall systems are generally of two varieties, namely xe2x80x9cstickxe2x80x9d or xe2x80x9cunitized.xe2x80x9d The stick curtain wall system is one in which the primary structural framing components are erected individually in the field, with vertical mullions typically attached to the floor slabs, with horizontals subsequently attached to the vertical mullions. Thereafter, the vision glass and spandrel materials are field installed into the assembled grid work.
The unitized curtain wall system is one in which the framing members are preassembled and erected in modules of a manageable size and weight. The wall modules are of a height generally equal to the building""s storey height. The assembled and pre-glazed modules are supported by connectors upon the outer area of the building floor. Modules are stacked upon each other in parallel rows, and adjacent modules are often connected together by means of male-female interlocking. Vertical and horizontal mating joints can either be dry-sealed with gaskets, or wet-sealed with field supplied sealants. Needless to say, quite a variety of techniques and hardware are available to generally fasten the wall modules to the structural elements of a building, in addition to the wide variation in constructing the modules in the first instance.
Although modules may be constructed as load bearing exterior walls, higher buildings require that each building floor support a row of modules of a height equal to the building""s storey height. The exterior wall system is normally supported on spaced apart vertical mullions. The vertical mullions are structurally connected to the building perimeter frame to provide two structural functions, namely to support the dead weight of the exterior wall system, and to resist reaction forces transmitted from the exterior wall system due to lateral (wind and/or earthquake) loads. Commonly used anchorage placements for joining the mullions to the building are located along the edges of the roof and floor slabs. In addition to lateral load resisting requirements, the functional requirement of the curtain wall includes water tight performance and maintaining a certain degree of air tightness for the consideration of thermal efficiency. An important consideration towards this end, is the effect of the relative deflection along the edges of the slabs between floors due to the variable live loads and the effect of building frame interstory movements due to lateral forces.
As architects continue to be called upon to design more aesthetically pleasing structures, and advances are made in cladding technology/material science, structural soundness, typically manifest in the form of economic viability/feasibility, remains the touch stone of cladding innovation. For example, structures such as the Philadelphia Regional Performing Arts Center, presently under construction, and the Shanghai Communication Center evidence the advances being made in cladding systems, more particularly in the area of glazed elements supported by a system of prestressed cables. Be this as it may, there remains a need for a self-bearing flexible curtain wall system, more particularly, a system wherein a matrix of kinematically integrated cladding panels includes vertically adjacent panels which are load bearing (i.e., dead load is transferred down along the vertical linkages between vertically adjacent panels).
A self-bearing flexible curtain wall system is provided, the system including a matrix of unitized kinematically integrated cladding panels flexibly joined to a structural member as for example, a prestressed, substantially vertical, cable or cable like element (e.g., rod, bar, etc.). Adjacent cladding panels of the matrix of unitized cladding panels are responsively linked horizontally and vertically for horizontal and vertical rotation. Horizontally adjacent cladding panels of the matrix of unitized cladding panels are responsively joined to a structural member via an anchor fixture, which allows the cladding panels to remain in a substantially static condition when the cables move along wall elevation due to main structure movement and/or distortion. More specific features and advantages will become apparent with reference to the DETAILED DESCRIPTION OF THE INVENTION, appended claims, and the accompanying drawing figures.